Geochemistry of coexisting depleted and enriched Paringa Basalts, in the 2.7 Ga Kalgoorlie Terrane, Yilgarn Craton, Western Australia: Evidence for a heterogeneous mantle plume event

doi:10.1016/j.precamres.2009.08.002

Precambrian Research

Volume 174, Issues 3–4, November 2009, Pages 287-309

https://doi.org/10.1016/j.precamres.2009.08.002 Get rights and content

Abstract

Depleted and enriched Paringa Basalts form the uppermost part of the Upper Basalt Unit of the Kambalda Sequence in the 2720–2680 Ma Kalgoorlie Terrane, and provide a window into compositionally and isotopically heterogeneous asthenosphere. Depleted examples of the basalts are compositionally restricted with Mg# between 61 and 57, and Ni between 166 and 73 ppm. On REE and primitive-mantle normalised diagrams they are characterised by: (1) near-flat REE patterns with a small range of LREE depletion ((La/Sm)_N 1.01–0.76); (2) neither Ce nor Eu anomalies; (3) Nb/Th ratios of 8.7–12, variably greater than the primitive mantle value of 8; and (4) no negative primitive-mantle normalised P or Ti anomalies relative to neighbouring REE. They have compositions similar to Neoarchean tholeiitic basalts associated with komatiites, and ɛ_Nd 2.7 Ga values of +1.3 to + 2.2, in keeping with the majority of crustally uncontaminated Neoarchean basalts and komatiites. Enriched counterparts of the Paringa Basalt are compositionally varied, with Mg# 76–53 and Ni 391–73 ppm. On REE and primitive-mantle normalised diagrams, they feature: (1) systematically fractionated LREE [(La/Sm)_N = 2.1–3.1)]; (2) HREE mostly ∼1, with outliers to 1.6; (3) neither Ce nor Eu anomalies; (4) low Nb/Th ratios of 0.7–1.6; and (5) strong negative primitive-mantle normalised P and Ti anomalies. Epsilon Nd values are −1.7 to −4.4; and there is no correlation of ɛ_Nd with indices of crustal contamination such as (La/Sm)_N or Nb/Th ratios. This basaltic suite has previously been interpreted as either boninitic or crustally contaminated komatiite. Assimilation-fractional crystallisation (AFC) modeling was conducted using a komatiite as parental liquid. Contaminants used in this modeling were local trondhjemite-tonalite-dacite (TTD) Black Flag Group (BFG), average high-Ca granites of the Yilgarn Craton, and average upper-, middle-, or lower continental crust of Taylor, S.R., McLennan, S.M. (1985). The Continental Crust: Its Composition and Evolution. Blackwell Scientific Publications, Oxford, 312 pp.]. Neither any of the average Archean crustal compositions match the AFC trends, nor does the BFG. High-Ca granites do match the trends, as does average modern upper crustal composition but the former have depleted mantle Nd-isotope compositions. There are numerous problems with a model of assimilation of continental crust in the genesis of the enriched Paringa Basalts, including coherent REE patterns over a range of Mg#, and Nb-, P-, and Ti-anomalies that do not increase with Th or (La/Sm)_N. Enriched Paringa Basalts are compositionally distinct from Mg-rich continental flood basalts that feature greater contents of Ti, and other incompatible elements, with fractionated HREE, or boninites, picrites, or medium-K basalts from intraoceanic arcs. Rather, these basalts are interpreted to result from recycling of older continental crust into the mantle source of the plume from which the Kambalda Sequence komatiites and basalts erupted. The two distinct compositional and isotopic types record a heterogeneous mantle plume, possibly erupted at a rifted craton margin.

Section snippets

Introduction and scope

Neoarchean greenstone terranes globally record a number of volcanic associations. Komatiites and associated basalts are generally interpreted as products of anomalously hot mantle plumes, erupted in ocean basins or continental margins (Arndt, 1994, Arndt, 2008, Hollings et al., 1999). Where there is a combination of field, trace element, and isotopic evidence for the absence of crustal contamination, basalts are tholeiitic with near-flat REE patterns over a range of REE abundances, and both

Regional geological setting

The Neoarchean (2800–2600 Ma) Eastern Goldfields Superterrane (EGST) forms the easternmost portion of the Yilgarn Craton (Myers, 1997, Barley et al., 2003, Barley et al., 2008, Krapez, 2006). This Superterrane comprises elongated, narrow to arcuate greenstone belts, composed of deformed and metamorphosed volcanic and sedimentary rocks, intruded by numerous granitoids and high-level intermediate to silicic porphyries. According to Barley et al., 1998a, Barley et al., 1998b, Barley et al., 2002,

Volcanic facies and textures

The Paringa Basalt is part of the Upper Basalt Unit of the Kambalda Sequence (Fig. 2). It is composed of fine- to medium-grained massive or pillowed mafic flows. The massive lavas most likely represent tabular or sheet flows. Medium- to coarse-grained gabbroic rocks are present in both the upper and lower parts of the Paringa Basalt sequence and may represent the central part of thick flows. Some flows contain varioles (up to 4–5 mm in diameter), commonly coalesced, giving a bleached appearance

Analytical methods

Abundances of major and selected trace elements were determined at Geoscience Australia, Canberra, using wavelength-dispersive X-ray Fluorescence Spectrometry (XRF: Philips XRF PW 2404). The concentration of the major elements (Si, Ti, Al, Fe, Mn, Mg, Ca, Na, K, P and S) was determined on fused disks using methods similar to those of Norrish and Hutton (1969). Precision for these elements is better than ±1% of the reported values. The minor elements Ba, Cr, Cu, Ni, Sc, V, Zr were determined on

Magma series

Based on the Jensen (1976) triangular diagram, depleted Paringa Basalt plots in the high-magnesium tholeiitic basalt (HMTB) field, whereas the enriched counterpart extends across the komatiitic-basalt and HMTB fields (Fig. 5). The enriched Paringa Basalt plots as calc-alkaline on the FeO*/MgO versus SiO₂ diagram of Miyashiro (1974; not shown) for distinguishing tholeiitic from calc-alkaline magma series, and as basaltic andesite on the discrimination diagram of Winchester and Floyd (1976; not

Alteration and metamorphism

Given that all rocks in the Kalgoorlie Terrane have undergone sea-floor hydrothermal alteration, poly-phase deformation, and greenschist to amphibolite facies metamorphism, variable element mobility is a possibility. In order to minimize the effects of these secondary processes, samples were carefully selected in the field by avoiding those sites that are most susceptible to chemical changes, such as shear zones, brecciated domains, and areas containing multiple veins and bleaching.

Geodynamic implications and conclusions

Crustally uncontaminated, depleted Paringa Basalts have systematically positive Nb anomalies of within-plate asthenospheric melts and plot along the MORB-OIB array in Th/Yb versus Nb/Yb coordinates, not above the array as for arcs basalts (cf. Pearce, 2008; not shown). Accordingly, the MORB-OIB array was established by the Neoarchean (Wyman and Kerrich, 2009). There is field evidence for synvolcanic extension, textural evidence for submarine eruption, and absence of significant crustal

Acknowledgements

This paper forms part of Nuru Said's PhD project, funded by a University of Western Australia postgraduate scholarship. The whole-rock analyses were generously funded by Professor T.C. McCuaig, Director of the Centre for Exploration Targeting, School of Earth and Environment, who is gratefully acknowledged. Helen Waldron of Genanalysis Laboratory Services and Dr David Champion of Geoscience Australia are acknowledged for the whole-rock geochemical analyses and for ensuring the quality of the

References (166)

N.T. Arndt
Archean komatiites
N.T. Arndt
Why was flood volcanism on submerged continental platforms so common in the Precambrian?
Precambrian Research
(1999)
N.T. Arndt et al.
Crustally contaminated komatiites and basalts from Kambalda, Western Australia
Chemical Geology
(1986)
J. Ayer et al.
Evolution of the southern Abitibi greenstone belt based on U–Pb geochronology: autochthonous volcanic construction followed by plutonism, regional deformation and sedimentation
Precambrian Research
(2002)
M.E. Barley et al.
Physical volcanology and geochemistry of a Late Archean volcanic arc: Kurnalpi and Gindalbie Terranes, Eastern Goldfields Superterrane, Western Australia
Precambrian Research
(2008)
M.E. Barley et al.
The Late Archean bonanza: metallogenic and environmental consequences of the interaction between mantle plumes, lithospheric tectonics and global cyclicity
Precambrian Research
(1998)
R. Bateman et al.
Archean mafic magmatism in the Kalgoorlie area of the Yilgarn Craton, Western Australia: a geochemical and Nd isotopic study of the petrogenetic and tectonic evolution of a greenstone belt
Precambrian Research
(2001)
J. Blichert-Toft et al.
The Nd and Hf isotopic evolution of the mantle through the Archean. Results from the Isua supracrustals, West Greenland, and from the Birimian terranes of West Africa
Geochimica et Cosmochimica Acta
(1999)
A.E. Boudreau
PELE- a version of the MELTS software program for the PC platform
Computer and Geoscience
(1999)
S.J.A. Brown et al.
The Late Archean Melita Complex, Eastern Goldfields, Western Australia: shallow submarine bimodal volcanism in a rifted arc environment
Journal of Volcanology and Geothermal Research
(2002)

S.E. Bryan et al.

Revised definition of Large Igneous Provinces (LIPs)

Earth Science Reviews

(2008)

W.E. Cameron et al.

Boninite petrogenesis: chemical and Nd–Sr isotopic constraints

Earth and Planetary Science Letters

(1983)

I.H. Campbell et al.

A two-stage model for the formation of the granite-greenstone terrains of the Kalgoorlie-Norseman area, Western Australia

Earth and Planetary Science Letters

(1988)

D.C. Champion et al.

Geochemistry and Sm-Nd isotopic systematics of Archean granites of the Eastern Goldfields Province, Yilgarn Craton, Australia: constraints on crustal growth

Precambrian Research

(1997)

C. Chauvel et al.

The Sm-Nd age of Kambalda volcanics is 500 Ma too old

Earth and Planetary Science Letters

(1985)

J.C. Claoué-Long et al.

The age of the Kambalda greenstones resolved by ion microprobe: implications for Archean dating methods

Earth and Planetary Science Letters

(1988)

K.C. Condie

Greenstones through time

A.J. Crawford et al.

Tectono-magmatic evolution of the West Philippine-Mariana region and the origin of boninites

Earth and Planetary Science Letters

(1981)

D.J. De Paolo

Trace elements and isotopic effects of combined wallrock assimilation and fractional crystallisation

Earth and Planetary Science Letters

(1981)

P.R. Hamlyn et al.

Precious metals in magnesian low-Ti lavas: implications for metallogenesis and sulfur saturation in primary magmas

Geochimica et Cosmochimica Acta

(1985)

R.L. Hickey et al.

Geochemical characteristics of boninite series volcanics: implications for their source

Geochimica et Cosmochimica Acta

(1982)

P. Hollings et al.

Trace element systematic of ultramafic and mafic volcanic rocks from the 3 Ga North Caribou greenstone belt. North western Superior Province

Precambrian Research

(1999)

P. Hollings et al.

Light rare earth element depleted to enriched basaltic flows from 2.8 Ga to 2.7 Ga greenstone belts of the Uchi Subprovince, Ontario, Canada

Chemical Geology

(2006)

P. Hollings et al.

Trace element and Sm–Nd systematics of volcanic and intrusive rocks from the 3 Ga Lumby Lake greenstone belt, Superior Province; evidence for Archean plume–arc interaction

Lithos

(1999)

P. Hollings et al.

Komatiite–basalt–ryholite volcanic associations in Northern Superior greenstone belts: significance of plume–arc interaction in the generation of the proto-continental Superior Province

Lithos

(1999)

H.S. Huppert et al.

Cooling and contamination of mafic and ultramafic lavas during ascent through continental crust

Earth and Planetary Science Letters

(1985)

K.P. Jochum et al.

Nb–Th–La in komatiites and basalts: constraints on komatiite petrogenesis and mantle evolution

Earth and Planetary Science Letters

(1991)

A.C. Kerr

Oceanic plateaus

R. Kerrich et al.

Trace element systematics of Mg-, to Fe-tholeiitic basalt suites of the Superior Province: implications for Archean mantle reservoirs and greenstone belt genesis

Lithos

(1999)

R. Kerrich et al.

Geochemical systematics of 2.7 Ga Kinojevis Group (Abitibi), and Manitouwadge and Winston Lake (Wawa) Fe rich basalt–rhyolite associations: Backarc rift oceanic crust

Lithos

(2008)

R. Kerrich et al.

Boninite series low Ti-tholeiite associations from the 2.7 Ga Abitibi greenstone belt

Earth and Planetary Science Letters

(1998)

K. Konishi et al.

MORB in the lowermost mantle beneath the western Pacific: evidence from waveform inversion

Earth and Planetary Science Letters

(2009)

N. Kositcin et al.

SHRIMP U-Pb zircon age constraints on the Late Archean tectonostratigraphic architecture of the Eastern Goldfields Superterrane, Yilgarn Craton, Western Australia

Precambrian Research

(2008)

B. Krapez et al.

Age constraints on recycled crustal and supracrustal sources of Archean metasedimentary sequences, Eastern Goldfields Province, Western Australia: evidence from SHRIMP zircon dating

Tectonophysics

(2000)

Y. Lahaye et al.

The influence of alteration on the trace-element and Nd isotopic compositions of komatiites

Chemical Geology

(1995)

C.M. Lesher et al.

REE and Nd isotope geochemistry, petrogenesis and volcanic evolution of contaminated komatiites at Kambalda, Western Australia

Lithos

(1995)

C. Manikyamba et al.

Geochemical systematics of komatiite-tholeiite and adakitic-arc basalt associations: the role of mantle plume and convergent margin in formation of the Sandur Superterrane, Dharwar craton, India

Lithos

(2008)

M.T. McCulloch et al.

Geochemical and geodynamical constraints on subduction zone magmatism

Earth and Planetary Science Letters

(1991)

J.S. Myers

Preface: Archean geology of the Eastern Goldfields of Western Australia – regional overview

Precambrian Research

(1997)

N.T. Arndt

Komatiite

(2008)

N.T. Arndt et al.

Geochemistry of Munro Township basalts

Arndt, N.T., Bruzak, G., Reischmann, T., 2001. The oldest continental and oceanic plateaus: geochemistry of the basalts...

M.E. Barley

Incompatible-element enrichment in Archean basalts: a consequence of contamination by older sialic crust rather than mantle heterogeneity

Geology

(1986)

M.E. Barley et al.

An integrated geological and metallogenic framework for the eastern Yilgarn Craton: developing geodynamic models of highly mineralised Archean granite-greenstone terranes

Australasian Mineral Industry Associoation, Report

(2003)

Barley, M.E., Brown, S.J., Krapez, B., Cas, R.A., 2002. Tectonostratigraphic analysis of the eastern Yilgarn Craton: an...

M.E. Barley et al.

Late Archean Ti-rich, Al-depleted komatiites and komatiitic volcaniclastic rocks from the Murchison Terrane in Western Australia

Australian Journal of Earth Sciencess

(2000)

Barley, M.E., Krapez, B., Brown, S.J.A., Hand, J., Cas, R.A.F., 1998b. Mineralised volcanic and sedimentary successions...

Bennett, V.C., 2003. Compositional evolution of the Mantle. In: Carlson, R.W. (Ed.), Treatise of Geochemistry, vol. 2,...

R.A. Binns et al.

Metamorphic patterns and development of greenstone belts in the Eastern Yilgarn Block, Western Australia

Blewett, R.S., Czarnota, K., 2007. A new integrated tectonic framework of the Eastern Goldfields Superterrane. In:...

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Geochemistry of coexisting depleted and enriched Paringa Basalts, in the 2.7 Ga Kalgoorlie Terrane, Yilgarn Craton, Western Australia: Evidence for a heterogeneous mantle plume event

Abstract

Section snippets

Introduction and scope

Regional geological setting

Volcanic facies and textures

Analytical methods

Magma series

Alteration and metamorphism

Geodynamic implications and conclusions

Acknowledgements

Precambrian Research

Chemical Geology

Precambrian Research

Precambrian Research

Precambrian Research

Precambrian Research

Geochimica et Cosmochimica Acta

Computer and Geoscience

Journal of Volcanology and Geothermal Research

Earth Science Reviews

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Precambrian Research

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Geochimica et Cosmochimica Acta

Geochimica et Cosmochimica Acta

Precambrian Research

Chemical Geology

Lithos

Lithos

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Lithos

Lithos

Earth and Planetary Science Letters

Earth and Planetary Science Letters

Precambrian Research

Tectonophysics

Chemical Geology

Lithos

Lithos

Earth and Planetary Science Letters

Precambrian Research

Komatiite

Geochemistry of Munro Township basalts

Incompatible-element enrichment in Archean basalts: a consequence of contamination by older sialic crust rather than mantle heterogeneity

Geology

An integrated geological and metallogenic framework for the eastern Yilgarn Craton: developing geodynamic models of highly mineralised Archean granite-greenstone terranes

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Late Archean Ti-rich, Al-depleted komatiites and komatiitic volcaniclastic rocks from the Murchison Terrane in Western Australia

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